1. Field of the Invention
The present invention relates generally to a motor vehicle with a handlebar, and more particularly to such a handlebar motor vehicle having a hydraulically operated power steering system.
2. Description of the Relevant Art
There have heretofore been proposed many power steering systems for operating a servo system by utilizing the difference between angular displacements of input and output shafts. For example, Japanese Laid-Open Patent Publication No. 47(1972)-22844 discloses a hydraulically operated power steering system in which input and output shafts are disposed concentrically with each other, and a control valve mechanism and a feedback mechanism are interposed between the input and output shafts, with a rotary hydraulic motor being coupled to the output shaft. The power steering system of the disclosed type is generally employed in a motor vehicle having a steering wheel wherein the input and output shafts rotate through more than 360.degree.. In order to meet such a large angle of rotation of the input and output shafts, however, the hydraulic motor assembly, in particular, is structurally complex since it requires a device for switching over hydraulic ports. A power steering system including a straight-motion cylinder-type hydraulic motor has also been proposed. This power steering system is also considerably complex in structure inasmuch as it requires a mechanism for converting reciprocating power of the cylinder to rotary power.